Freedom! These smartwatches leave the phone behind

SANTA MONICA, Calif. — Strap on the Samsung Gear S or the Sony SmartWatch 3 if you want to take a jog on the beach or head out for a bike ride without your phone clunking along.

One of my frustrations with early smartwatches has been how little they can do on their own. Sure, your phone might be with you most of the time, but sometimes you want to leave it behind. The Gear S and SmartWatch 3 still need to be close to an Android phone for a lot of things, but both do more solo than other smartwatches.

Samsung Gear S ($300 to $400, plus $5 or $10 monthly service fee)

The Gear S isn’t the only smartwatch to notify you about new messages, Facebook updates and weather. It isn’t alone in having an alarm clock, music playback and apps for tracking steps and exercise.

So what makes this watch stand out? Cellular connectivity. Other smartwatches use a Bluetooth wireless connection linked to your phone to receive calls, send texts and perform other tasks. The Gear S can do all that on its own.

The watch gets its own phone number. When your phone is nearby, calls and texts from the watch will go through your phone and carry your regular number. When you want to step away, you can still have calls, texts and other notifications forwarded to the watch. But calls you make and texts you send from the watch might get your watch’s number.

I’ve used the Navigator app to get directions, though advance features such as rerouting when lost or vibrations at turns didn’t work for me without the phone nearby. Many smartwatches are inaccurate exercise trackers, but with built-in GPS, the Gear S can more precisely track how far you run. The watch has a touch keyboard with tiny keys; it’s clunky to use, but you can dictate messages by voice, too. The watch can also play music stored on the device or streamed through Samsung’s free Milk service.

The unit I tested came from AT&T, which charges $10 a month for 4G service on top of the $300 for the device ($200 with a two-year service agreement). Sprint charges $10 for 3G service, while it costs $5 a month for Verizon 3G and T-Mobile 4G service. The device costs $350 to $400 with those three.

Sony Smartwatch 3 (starts at $250)

Sony’s SmartWatch 3 joins the Gear S in having built-in GPS, something many smartwatches still lack. At least three running apps — iFit Outside, RunKeeper and My Tracks — use the watch’s GPS and work without a companion phone. As with the Gear S, I found the Sony watch quite accurate in normal settings, such as runs in Los Angeles and Las Vegas. In New York, my stand-alone GPS watch from Garmin does better at factoring in tall buildings that block or distort GPS signals. But the SmartWatch still does better than many watches that rely solely on an accelerometer sensor.

You can also play music stored on the device, though the watch lacks a speaker so you need a Bluetooth headset. (Offline music playback is also common in other watches).

Sorry, the SmartWatch 3 has no cellular service, so you can’t make or receive calls or texts, take notes or use the map function unless your phone is in your pocket or purse.

Wait for Apple watch?

People with iPhones will need to wait until April to see what, if any, stand-alone features will come with Apple’s smartwatch. The ones out so far typically work only with Android phones. But if you have an Android phone, the Samsung and Sony watches stand out among the many choices.